Almost every player in the nation's capital is hooked in to the social networking giant. But it still has catching up to do in making its influence count.

Reporting from Washington and San Francisco — By conventional measures, Facebook is still a bit player in Washington — with a small but growing staff and a lobbying budget that's less than one-tenth that of Google's.

But, oh, the friends it has.

Members of Congress are among the most active and enthusiastic users of the popular social network, using Facebook pages to communicate with constituents and interest groups about their legislative positions, home district visits and campaign events.

Recognizing the benefit of having friends in government, Facebook has dispatched staffers around Washington, giving tutorials about how to use its network to groups such as the House Republican New Media Caucus and the Senate Press Secretaries Assn. Executives from Palo Alto have flown in to meet with top lawmakers and White House officials to discuss issues vital to the company, such as online privacy, as the company works to expand its presence in the nation's capital.

Sen. Mark Warner (D-Va.) popped into Facebook's headquarters recently to hang out with its chief executive, Mark Zuckerberg, and pop singer Katy Perry. He sent a message to his more than 16,000 followers on Twitter that the trio discussed the "need to support innovation in America."

"I'm sure at this point almost every member of Congress is on Facebook and is actively using it to reach out to their constituents," said David All, a former Capitol Hill aide who runs a consulting firm focused on maximizing the use of technology. "For politicians to feel the benefits of a platform the size and scope of Facebook, it certainly helps them with regard to any positions they may take on issues."

Some fret that the relationship may be getting too friendly. Even President Obama mentioned the company as an exemplar of innovation in his State of the Union address.

"Increasingly, if you want to get elected or sell a product, you have to be on Facebook," said Jeff Chester, executive director of the Center For Digital Democracy. "That gives them tremendous heft when it comes to lobbying in this town and around the world."

Facebook says there's nothing wrong with being chummy. "These are tools and techniques that are common to all organizations — for-profit and not-for-profit — in Washington to educate and create greater awareness and understanding about policy issues," said Elliot Schrage, Facebook's vice president of global communications, marketing and public policy.

Members of Congress say the fact that they use Facebook doesn't mean they will favor the company.

"It's helpful that I'm more familiar with their issues than I might be with the issues of certain other groups, but I still make all of my decisions based on the Constitution and what I think is the appropriate decision for all of my constituents," Rep. Justin Amash (R-Mich.) said.

Still, Amash, 30, is an unabashed Facebook fan. As a Michigan state legislator, Amash used Facebook to explain his every vote. And like many politicians, he credited his Facebook page with helping him connect with voters and win his race for Congress.

The goodwill Facebook already had with Amash got a boost when the company invited him last month to discuss his experiences in a new video series called Facebook DC Live. Amash and Facebook's Washington office both touted the interactive chat on their Facebook pages.

Sitting on a bright yellow couch in the company's small D.C. office, Amash gushed about Facebook.

"It's really bringing people together," Amash told the audience watching the live streamed chat. "It's connecting our world and connecting our society, and it's really transforming the way we interact."

Despite such support, Facebook's treatment of its users' personal information has come under increasing scrutiny in Washington.

"I love Facebook," said Sen. Mark Begich (D-Alaska), who regularly updates his page from his iPad. "But the consistent item they run into trouble with is disclosing information to third parties for the economic benefit of Facebook."

Last spring, Begich and three other senators wrote to Zuckerberg complaining about a pilot program that shared users' personal information with three outside websites. Facebook made changes about a month later.

But privacy advocates said there were still problems. Last fall, Reps. Joe Barton (R-Texas) and Ed Markey (D-Mass.) wrote to Zuckerberg with 18 detailed questions about a series of reported privacy breaches that involved personally identifiable information from millions of Facebook users being transmitted to third-party applications.

And on Wednesday, Barton and Markey fired off another letter to Zuckerberg, expressing concerns about Facebook's plans to share user addresses and mobile phone numbers with developers and websites.

"I don't know what it is about Facebook and privacy," said Marc Rotenberg, executive director of the Electronic Privacy Information Center in Washington. "It's like a mosquito to a light."